Clark Regional Wastewater District

Transcription

1 2016 Clark Regional Wastewater District Infiltration and Inflow Report For Salmon Creek Treatment Plant February 13, 2017 In Compliance with the NPDES Waste Discharge Permit No. WA Special Condition S4.E

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3 TABLE OF CONTENTS 2016 Clark Regional Wastewater District INFILTRATION AND INFLOW REPORT Overview... 1 Monitoring Program and Rehabilitation Projects... 3 Appendix Appendix A - Annual Infiltration/Inflow (I/I) Report (DOE form) Appendix B - Flow Analysis Data Appendix C - Monthly Flow and Appendix D - ERU and Sewer Line Data

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5 2016 Infiltration and Inflow Report Clark Regional Wastewater District OVERVIEW The Clark Regional Wastewater District (District) was formed in The District has always maintained a comprehensive construction specification, inspection and maintenance program to minimize infiltration and inflow (I/I) into the system. As a result, the system flow characteristics perform well below the non-excessive criteria as established in the EPA Infiltration/Inflow Analysis and Project Certification (Ecology publication 97-03). Beginning in 2016, the District began conveying a portion of the flow generated in the City of Ridgefield service area to the Salmon Creek Treatment Plant. Currently, all flow tributary to the Pioneer Canyon Pump Station is conveyed through the Discovery Corridor Wastewater Transmission System and ultimately to the Salmon Creek Treatment Plant. The Pioneer Canyon Pump Station receives about 0.1 (1,358 Equivalent Residential Units (ERUs)) of flow generated in the City of Ridgefield. The Ridgefield Treatment Plant processes the remaining flow generated in Ridgefield. The additional flow to Salmon Creek is incorporated into this report. ANALYSIS The District s average dry weather and wet weather I/I rates are well below what would generally be considered excessive. Average dry weather flows greater than 120 gallons per capita per day (gpcd) indicate excessive infiltration. Infiltration occurs during periods of high seasonal groundwater and dry weather with little or no rainfall. The District s infiltration remains well below excessive at only 79 gpcd. Average wet weather flows greater than 275 gpcd indicate excessive inflow. Inflow occurs during periods of wet weather with significant rainfall resulting in ponding and surface runoff. The District s inflow remains well below excessive at only 106 gpcd. For the purpose of this report, population calculations have been based on population equivalents. This method calculates a population based on the total number of ERUs multiplied by the planning assumption of people per ERU. This assumption is 2.43 people per ERU for the Salmon Creek Treatment Plant (CH2M HILL, 2004 SCTP Phase 4). The calculation for population equivalent includes commercial and industrial ERUs in addition to residents of the area. At the beginning of 2016, the District had approximately 32,800 ERU s with a population equivalent of roughly 80,000 in the Salmon Creek tributary area. The City of Ridgefield component adds another 381 ERUs with a population equivalent of about 925. Page 1

6 As shown in Appendix A, the District s 2016 I/I of 1.73 represent a 58% increase compared to the 2003 base year. To better understand I/I trends in the system, the District reviews the average monthly flows and rainfall for the available records between January 1997 and December That data shows that 2013 and 2003 represent the lowest I/I years on record. The District s I/I averaged 1.54 over the past 19 years. Reviewing years with similar total rainfall, the 2016 I/I does not appear to be out of trend with historical performance. Also, the excessive inflow and infiltration calculations do not lead us to believe that the system is experiencing higher than normal I/I. TABLE I/I AND RAINFALL Year Min of Average Monthly Flow () Max of Average Monthly Flow () I / I Annual Average Page 2

7 Monitoring Program and Rehabilitation Projects Introduction The District places an emphasis on good design and inspection to minimize I/I into the system. However, as pipes age, a variety of methods for the monitoring and identification of I/I are necessary to use. This includes yearly review of pump station records, treatment plant flow reports, trunk line flow monitoring, smoke testing, visual inspection of manholes and closed circuit television (CCTV) camera inspection. Through these efforts, the District is able to locate areas of concern for follow-up investigation and correction. Cross-Connections For issues on private property (i.e., stormwater cross connections, roof drains or broken laterals), the District contacts the homeowner and works with them to correct the situation. The District typically addresses issues that are within public right-of-way. All side sewer connections (between right-of-way and building envelope) are permitted and inspected by the District. Following the December 2015 storm events, the District performed smoke testing at various locations upstream of known high flows. This work revealed two significant sources of inflow where broken or missing cleanout caps were draining stormwater into the wastewater system. Both locations were repaired in the summer of New Construction The District addresses I/I by inspecting all new systems during construction, including all mainlines, manholes and individual laterals. In addition, during plan review and field inspection, the District reviews the need for inflow dishes or watertight locking lids to control inflow. The District addresses infiltration by requiring manhole joints to be externally sealed in areas of high groundwater, vacuum testing of 50% of all new manholes and air testing of all new gravity mainlines. Flow Monitoring The District owns several FloDar ultrasonic flow meters that are used to measure flows where I/I is suspected. The District also monitors its 64 pump stations as well as our four motor operated valves (MOV s). Daily and annual review of the flow data, help us identify the potential for I/I. In addition, the two satellite service areas (Meadow Glade and Hockinson) that are served by STEP systems have individual flow meters at their termination. The District continues to deploy and collect flow data from 10 FloDar ultrasonic flow meters during both wet and dry weather flows. That data is currently being Page 3

8 used to calibrate the District s wet and dry weather flows as part of the General Sewer Plan update. Rehabilitation The District inspects all gravity mains and trunk sewers with CCTV cameras every eight years to assess condition, I/I and other related issues. Results help inform the District s Six-Year Capital Program. The six-year program includes an annual I/I program as well as a Spot Repair program component. Both programs provide for completion of specific projects targeting the reduction of I/I in the system. The District completed manhole grouting at 15 locations in 2016, which will stop an estimated 25 gallons per minute of I/I, or 36,000 gallons per day. The District is currently preparing two cured-in-place pipe contracts for 2017 to stop infiltration and rehabilitate existing concrete pipes. Page 4

9 APPENDIX A ANNUAL INFILTRATION/INFLOW (I/I) REPORT

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13 APPENDIX B FLOW ANALYSIS DATA

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15 Salmon Creek Wastewater Management System - Clark Regional Wastewater District ANNUAL INFILTRATION/INFLOW REPORT 1/1/2016 to 12/31/2016 FLOW AND PRECIPITATION DATA POPULATION AND SEWER LINE DATA Average Monthly Flow () Total Monthly Precipitation (Inches) Population Served (Population Equivalent) Sewer Lines Added (Feet) MONTH Year Year MONTH Year Year January January February February March March B-1 April April May May June June July July August August September September October October November November December December Avg Flow / Total Rain Present Equivalent Total (feet) Low Month Total (miles) High Month Comments: Measured data presented in this report reflects the Clark Regional Wastewater District's capacity usage only. Battle Ground usage is reported separately.

16 Salmon Creek Wastewater Management System - Clark Regional Wastewater District ANNUAL INFILTRATION/INFLOW REPORT 1/1/2016 to 12/31/2016 DETERMINATION OF NON EXCESSIVE INFILTRATION DETERMINATION OF NON EXCESSIVE INFLOW EPA Infiltration Criteria 120 gpcd EPA Inflow Criteria 275 gpcd District Infiltration 79 gpcd District Inflow 114 gpcd Period Population Flow Rain Equivalent Period Flow Rain Population Equivalent B-2 Mar Jan Mar 29 Mar 30 Mar 31 Apr 01 Apr 02 Apr 03 Average Flow () Jan Jan Jan Jan Jan Jan Highest Inches Rain Average Flow Inches Rain () Comments: The seven day period of March 28 through April 3, 2016 was identified as a dry weather period within a period of seasonal high groundwater. Comments: The seven day period of January 12 through January 18, 2016 was identified as a period of significant rainfall with surface ponding and runoff. January 18 was the highest recorded daily flow during a storm event.

17 Salmon Creek Wastewater Management System - Clark Regional Wastewater District ANNUAL INFILTRATION/INFLOW REPORT 1/1/2016 to 12/31/2016 INFILTRATION/INFLOW SUMMARY PLANT DESIGN CAPACITY Year I/I % of % Over Max Base I/I Design Flow Peak Design Flow: Max Month Design Flow: % 16.9% Base Year: 2003 Design Population Equivalent: 86,989 People % 17.4% I/I: % 9.3% % 13.1% % 63.3% Comments: % 15.1% See Overview for I/I discussion. B-3 Average Flow () Average Flow and Precipitation Precipitation (Inches) Month 3 Average Flow () Total Monthly Precipitation (Inches) Comments: Design capacity represents total plant capacity. Present population and infiltration/inflow data included in this report represent Clark Regional Wastewater's usage only. Battle Ground usage is reported separately.

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19 APPENDIX C MONTHLY FLOW AND RAINFALL

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21 Salmon Creek Wastewater Treatment Plant Flow and Report C-1 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 1/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Total Min Max Average

22 Salmon Creek Wastewater Treatment Plant Flow and Report C-2 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 2/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ Total Min Max Average

23 Salmon Creek Wastewater Treatment Plant Flow and Report C-3 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 3/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Total Min Max Average

24 Salmon Creek Wastewater Treatment Plant Flow and Report C-4 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 4/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ Total Min Max Average

25 Salmon Creek Wastewater Treatment Plant Flow and Report C-5 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 5/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Total Min Max Average

26 Salmon Creek Wastewater Treatment Plant Flow and Report C-6 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 6/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ Total Min Max Average

27 Salmon Creek Wastewater Treatment Plant Flow and Report C-7 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 7/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Total Min Max Average

28 Salmon Creek Wastewater Treatment Plant Flow and Report C-8 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 8/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Total Min Max Average

29 Salmon Creek Wastewater Treatment Plant Flow and Report C-9 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 9/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ Total Min Max Average

30 Salmon Creek Wastewater Treatment Plant Flow and Report C-10 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 10/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Total Min Max Average

31 Salmon Creek Wastewater Treatment Plant Flow and Report C-11 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 11/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ Total Min Max Average

32 Salmon Creek Wastewater Treatment Plant Flow and Report C-12 Date Meadow Glade GPD Hockinson GPD Total BG Inf BG Only Total BG Eff Diff SC Inf SC Eff Diff BG SC 12/1/ /2/ /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Total Min Max Average

33 APPENDIX D ERU AND SEWER LINE DATA

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35 CLARK REGIONAL WASTEWATER DISTRICT SALMON CREEK TREATMENT PLANT SEWER CONNECTION REPORT Year: Jan Dec 2016 Multi Family/ Total Grand Line Construction Total Year to Date New Total Guesthomes Res/ New Total Total Line Total SCTP - All Month Residential Residential (*.8) Multi-Family Commercial Commercial ERU's Developer District Construction Miles Res 1,149.0 Multi-Family 88.0 Balance ERU's Comm 40.8 Forward Total 1,277.8 ERU'S Jan VTP Feb Res 21.0 Mar Multi-Family - D-1 Apr Comm - May Total 21.0 Jun RTP Jul Res Aug Multi-Family - Sep Comm 4.3 Oct Total Nov Permits Dec SCTP 963 Subtotals VTP 311 Total ERU's RTP 21 Total 1295 See reverse for explanation

36 D-2 January May September SCTP Union Prairie Business Park Bldg 2 SCTP Pioneer Vista Apartments SCTP Padden Employment Center NE 113th St Ste NE 15th Ave 9000 NE 64th Ave Rocket Delivery 0.3 Office 1.0 Seton Catholic High School 8.7 SCTP SCBP Westland North Bldg E Pool NE 13th St Ste 112 Apartment Bldg A 10.4 October Performance Air 0.2 Apartment Bldg B 19.2 SCTP Bowyers Marketplace Retail D NE 13th St Ste 116 Apartment Bldg C NE 119th St Image Broadband 0.3 Apartment Bldg D 19.2 Clear Choice Chiropractic NE 13th St Ste 104 Apartment Bldg E 19.2 SCTP Central Industrial Park Bldg Enivrolux Energy Systems NE 88th St 1.0 SCTP SCBP Westland North Bldg E Prairie Electric 1.5 February NE 13th St Ste 106 SCTP Felida Village Building 1 Silke 0.2 SCTP R South 11th Street 3600 NW 119th St Ste 201 SCTP Community Home Health Hospice 5525 S 11th St Backstairs NE 136th St WA Dept of Fish & Wildlife NW 119th St Ste 200 Care Center 1.4 SCTP R Union Ridge Lot 6 Apartment S Union Parkway SCTP Union Prairie Business Park Bldg 2 June Self Storage NE 113th St Ste 108 SCTP Felida Village Building Intermountain West Insulation NW 119th St Ste 100 November NE 113th St Ste 124 Pines Coffee 1.0 SCTP Ferenco Building Heritage Enterprises 0.2 SCTP nlight Photonics NW 3rd Ct NE 88th St Bldg E Appliance Refrigeration & Hospital 0.8 March Annual Review SCTP Felida Village Building December 3602 NW 119th St Ste 101 August SCTP Wubben Industrial Park Studio V 1.0 SCTP ULID NE 112th Ct Ste NE 15th Ave Ste 101 General Glass 4.0 Crossfit Untamed

37 CLARK REGIONAL WASTEWATER DISTRICT MEADOWGLADE AREA SALMON CREEK TREATMENT PLANT SEWER CONNECTION REPORT Year: Jan Dec 2016 Multi Family/ Total Grand Line Construction Total New Total Guesthomes Res/ New Total Total Line Total Month Residential Residential (*.8) Multi-Family Commercial Commercial ERU's Developer District Construction Miles Balance ERU's Forward Jan Feb Mar D-3 Apr May Jun Jul Aug Sep Oct Nov Dec Subtotals Total ERU's See reverse for explanation

38 SCTP MG SCTP MG February Hardship mobile home conversion NE 110th Ave Guesthome March Columbia Adventist Academy NE 112th Ave Ste 102 Alpha Impressions D-4

39 CLARK REGIONAL WASTEWATER DISTRICT HOCKINSON AREA SALMON CREEK TREATMENT PLANT SEWER CONNECTION REPORT Year: Jan Dec 2016 Multi Family/ Total Grand Line Construction Total New Total Guesthomes Res/ New Total Total Line Total Month Residential Residential (*.8) Multi-Family Commercial Commercial ERU's Developer District Construction Miles Balance ERU's Forward Jan Feb D-5 Mar Apr May Jun Jul Aug Sep Oct Nov Dec Subtotals Total ERU's

40 CLARK REGIONAL WASTEWATER DISTRICT RIDGEFIELD AREA SALMON CREEK TREATMENT PLANT SEWER CONNECTION REPORT Year: Jan Dec 2016 Multi Family/ Total Grand Line Construction Total New Total Guesthomes Res/ New Total Total Line Total Month Residential Residential (*.8) Multi-Family Commercial Commercial ERU's Developer District Construction Miles Balance ERU's Forward Jan Feb Mar D-6 Apr May Jun Jul Aug Sep Oct Nov Dec Subtotals Total ERU's See next page for explanation

41 SCTP R January Carolees 888 S Hillhurst Rd Advanced Recovery D-7